Production of sod using a soil-less and based root zone medium

ABSTRACT

The present invention relates to a soil-less sand based root zone medium for the production of sod. The present invention is also directed to a method for the production of sod using a soil-less sand based root zone medium and a sod mat produced by the method of the present invention.

[0001] This application is a continuation of Ser. No. 08/509,172, filedJul. 31, 1995, now U.S. Pat. No. ______, which is a continuation-in-partof Ser. No. 08/225,818, now abandoned, which is a division of Ser. No.07/926,663, filed Aug. 7, 1992, now U.S. Pat. No. 5,301,466.

FIELD OF THE INVENTION

[0002] This invention relates to a method of producing turf grass in sodform. The invention is also directed to a composition for the use in theproduction of turf grass sod which is particularly well suited for useon sports surfaces such as stadium fields and golf courses. Theinvention also relates to a sod mat produced by the method of thepresent invention.

BACKGROUND OF THE INVENTION

[0003] The success of a sports turf grass sod (a mat of grass plantsgrown in surface soil and sliced horizontally into a thin layer for usein a place other than where grown) depends on the proper physicalcharacteristics of the root zone medium (the medium in which the sod isinitially grown) and the compatibility of that medium to the drainagebed and the root zone profiles (the area into which the root-system ofthe sod will grow) underlying the sports field surface where the sodwill be transplanted. Native topsoils used in sod production generallydo not have the physical characteristics which make them compatible withthe drainage beds and root zone profiles at the site of transplanting.Therefore, in most cases root zone medium must be provided to improvethe compatibility of sod growing medium and the existing root zoneprofile. Typically, root zone medium is compounded from available sand,soil and fibrous organic amendments such as wood fiber. Because ofextreme local variations in these materials, a high degree of expertiseis necessary to determine which root zone medium blends contain thedesired properties. Different lots of sand from the same pit may varyconsiderably in particle, size and shape. Native soils used in theseblends also vary greatly in particle, size and shape, as well as indegree of aggregation, acidity, fertility, soluble salt, and organicmatter content. Another variable in typical root zone medium blend isthe fibrous organic amendment.

[0004] It has long been the desire of sports fields managers and golfcourse superintendents to have a source of sod in which the growthmedium (root zone medium) matches or nearly matches and is thuscompatible with the existing root zone profiles of the areas to beplanted with sod.

[0005] Because of heavy compaction resulting from high traffic on sportsfields and golf greens, said is used extensively in root zone mediummixes. The proportion of said to other materials in the mix will varydepending on what other amendments are to be used, the water percolationrate desired, and the ultimate use of the playing surface. Under mostcircumstances, if conventional sod is used on these playing surfaces,layering occurs. Layering refers to the formation of an interfacebetween the fine soil particles of the root zone medium of the sod andthe more coarse sand particles of the root zone profile of thetransplant site. The layer formed by this process causes water flow tobe interrupted when passing through the sod, into the root zone of thetransplant site and the soil. As consistent percolation rates are veryimportant in the maintenance of these surfaces and to the establishmentof a suitable root system, great differences in particle size betweenthe root zone medium of the sod and the root zone of the transplantationsite which causes layering is obviously a great disadvantage.

[0006] The United States Golf Association (USGA) green section hasestablished guidelines for sand particle sizes which, when used in golfgreens, give the most consistent percolation rates, resists compactionby players and offers a good rot zone environment for grass plants.These guidelines often work extremely well for other sports fieldapplication but are occasionally modified to meet specific needs.

[0007] In U.S. Pat. No. 4,232,481, entitled “Carpet of Vegetable Matter”by Michel C. Chamoulaud, the production of sod or other vegetable matteris described. That patent teaches a compost layer made from wood barkwhich is crushed and gauged and spread onto a flat surface impermeableto plant roots. The compost mix is mixed with seeds before, during orafter the application to the flat surface. The roots of the plantsformed from the seed form a fabric embedded in a compost whichfacilitates the detachment of the sod from a flat surface.

[0008] In U.S. Pat. No. 4,941,282, by Gene Milstein entitled “WildflowerSod Mat A Method of Propagation”, the propagation of wildflower sod matsis described. The patent teaches a sod mat formed of sheets of poroussynthetic material, a layer of planting medium and viable wildflowerseeds which upon germination allows the root mass of the seeds tointermesh with the porous synthetic material thereby forming the sodmat. The patent teaches the planting medium composed of variousmaterials such as a composition of 50% sphagnum moss 49% vermiculite orperlite, and 1% nutritive material, capable of sustaining plant growth.

[0009] The present invention is directed to a soil-less sand based rootzone medium for the production of turf grass sod which has goodpercolation rates, good bulk density and resists compaction and whosecomposition may be altered so as to be compatible with the existing rootzone profile of the transplant site. The present invention also relatesto a method for production of turf grass sod using the soil-less sandbased root zone medium. Finally the invention is also directed to a sodmat produced by the method of the present invention which is suitablefor use on sports surfaces including stadium and golf courses.

SUMMARY OF THE INVENTION

[0010] It is an object of the invention to provide a soil-less, sandbased root zone medium useful in the production of turf grasses in sodform and which is capable of being formulated so as to be compatiblewith the root zone soil profile of the site to which the sod will betransplanted and which has high consistent percolation rates and resistscompaction, the root zone medium comprising:

[0011] (a) from about 60% by weight to about 100% by weight sand;

[0012] (b) from about 40% by weight to about 0% by weight organicamendment; and

[0013] (c) an effective amount of fertilizer.

[0014] It is preferred that the grains of sand used in the presentinvention have a uniform size ranging from about 0.05 mm to about 1 mm.

[0015] It is also an object of the present invention to provide a sodmat comprising a mat of turf grass and a layer of soil-less sand basedroot zone medium produced by the method of the present invention.

BRIEF DESCRIPTION OF THE FIGURES

[0016]FIG. 1 illustrates a rolled sod mat including turf grass, rootsystem, root zone medium and root impermeable layer.

DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention relates to a soil-less sand based root zonemedium useful in the production of sod and a method for the productionof turf grass sod using the same soil-less sand based root zone medium.The present invention also relates to a sod mat comprising a mat of turfgrass and a thin layer of the soil-less sand based root zone medium ofthe present invention (FIG. 1). Sod produced by the method of thepresent invention is highly resistant to compaction and meets USGAspecifications for water infiltration rates (from 2 inches to about 10inches per hour with an ideal rate of 4-6 inches per hour), bulk density(from about 1.2 gm/cc to about 1.6 gm/cc with an ideal bulk density from1.25-1.45 gm/cc), porosity (total 40-55% with a non-capillary minimum of15%) and water retention (12-25% by weight at a tension of 40 cm ofwater). Root zone media complying with these specifications promotesrapid growth of the turf grass and establishment of a dense root system.

[0018] The soil-less root zone medium of the present invention comprisesfrom about 60% by weight to about 100% by weight sand, from about 40% byweight to about 0% by weight organic amendment and an effective amountof nutrient material such as fertilizers (typically less than 1% byweight).

[0019] The sand utilized in the soil-less root zone mixture of thepresent invention should be of uniform size ranging from about 0.05 toabout 1 mm in size so as to allow consistent percolation rates inaccordance with USGA standards and to provide resistance to compaction.The size of the sand grains used in the present invention may beselected so as to be comparable in size and therefore compatible withthe root zone profile of the site to which the sod will be transplanted.The ability to select the appropriate sand size allows the user tocustomize the soil-less sand based root zone medium of the sod so as tobe optimally compatible with the root zone profile of the transplantsite. Soil-less sand based root zone medium containing this range ofsand content and grain size minimizes layering problems which can arisewhen sod is laid on soil of the transplantation site.

[0020] The soil-less sand based root zone medium of the presentinvention also contains from about 40% by weight to about 0% by weightorganic amendment. organic amendments aid in the control of waterpercolation and infiltration rates, in retention of moisture, and mayalso provide nutritional value to the grass plants in the form ofcarbon, nitrogen phosphorus and minerals. Organic amendments useful inthe present invention include but are not limited to, rice hull compost,milorganite, various peat mosses, fibrous plant material or fibrousvegetable matter.

[0021] The preferred organic amendment for use in the present inventionis canadian sphagnum peat moss. The preferred percentage of organic andamendment in the present invention is from about 30% by weight to about20% by weight of the soil-less sand based root zone medium. However, itis also recognized that the percentage of organic amendment may varydepending on the root zone composition on which the sod will betransplanted, and the specific uses of the turf being grown (e.g., golfcourse fairway, greens surfaces or other surfaces).

[0022] The composition of the present invention may also containeffective amounts (typically less than 1% by weight) of fertilizer tostimulate and enhance the growth of grass. These fertilizers may beselected from a wide variety of fertilizers including slow releasefertilizers, lime fertilizers and others. A preferred nutrient for thecomposition of the present invention has a ratio 1:1:1 ofnitrogen:phosphorous:potassium when used with stolons or plugs and 0:1:1nitrogen:phosphorous:potassium when used with seed. The criteria forselection of fertilizers for growth of various types of turf grass sodare well known in the art.

[0023] A preferred composition of soil-less sand based root zone mediumof the present invention includes about 20% by weight organic amendmentand about 80% by weight said and up to about 1% nutrient. However, rootzone medium composition may be varied in accordance with the presentinvention in order to be more compatible with the root zone profile ofthe site to which the sod will be transplanted or to meet performancestandards required by the specific use of the sod.

[0024] The root zone composition of the present invention is useful forgrowing a wide variety of turf grasses 1 (FIG. 1) beginning from seed,sprigs or plugs. The particular grass selected for growth in thecomposition of the present invention will depend on the ultimate use ofthe surface whether it be for use in a stadium, golf course or other usethe climate in which it will be used, and other environmental factors.

[0025] Another object of the present invention is a method forcultivating, developing and growing all varieties of turf grasses in sodfor using the soil-less sand based root zone medium of the presentinvention. The method of the present invention comprises the selectionof the appropriate amount of sand, the appropriate size sand grain so asto be compatible with the root zone profile of the area to which the sodwill be transplanted, the selection of an organic amendment, theselection of fertilizer if desired and the selection of turf grass typeto meet the specific needs of the end user. These selections will dependon the nature of the root zone on which the sod will be transplanted,the available nutrients, climatic conditions under which the sod will begrown, the percolation rates and water retention characteristics desiredand the use to which the sod will be put.

[0026] By way of example, in order to produce the soil-less sand basedroot zone medium of the present invention 3 (FIG. 1), the appropriateamount of sand of the appropriate size, and organic amendments are mixedusing general practices in wide spread use in the sod industry.Typically, ingredients can be mixed in a soil blender such as a“Greensmix”® Soil Blender *Waupaca, Wis.). Fertilizers and seeds mayalso be added at this stage and blended with sand and organic amendmentif so desired. Seed is typically added at a rate of 45 lbs/acre. Typicalfertilizer for soil growth is 0:1:1 when starting from seed. Uponthorough mixing, the composition is metered out (deposited) to theappropriate depth of from about 0.25 inches to about 1.0 inch on a rootimpermeable layer 5 (FIG. 1) Metering may be accomplished usingmachinery such as that described in U.S. Pat. No. 4,232,481, entitled“Carpet of Vegetable Matter” by Michel C. Chamoulaud, which isincorporated herein by reference, or other types of machinery well knownin the art. The root impermeable layer 5 may be made of syntheticmaterial such as plastic including polyethylene, rubber, porouspolyethylene, other plastics, filter cloth, non-woven materials such asAgryl P-30 or P-50, (Agrifabrics, Atlanta, Ga.) or other rootimpermeable materials. The root impermeable layer may be perforated toallow drainage of excess moisture. If perforations are used, they mustbe small enough to prevent roots from penetrating the layer. Upon layingdown of the soil-less sand based root zone medium onto the rootimpermeable layer, seed (if not yet added) stolons, sprigs or plugs arethen planted in the medium using standard procedures well known in thesod industry. For example, stolons are typically planted at a rate of600 bushels per acre. The choice of seed, stolon, sprig or plug will bedetermined by the type of turf grass desired. By way of non-limitingexample, grasses which may be started from stolons, sprigs or plugsinclude various Bermuda grasses, such as Tifway, Tifway II, Tifgreen,Tifdwarf, Zoysia grasses such as Myers Z-52, Casmere, and grasses suchas St. Augustine, and Centipede. By way of non-limiting example, grassesgrown from seed include bent grass such as Penncross, Pennlinks, SR1020and others. Other grasses grown from seed include Fescues, Ryes,Bluegrasses, Zoysias, Buffalo grasses and others. The quantity of plantmaterial used is based on normal sod establishment procedures which arewell known in the art. For example, when bent grass sod is desired, seedis usually evenly spread at a rate of about 50 lbs. per acre. Turf grassis then allowed to grow using standard cultivation procedures and whichare well known in the art and which include adequate watering andsupplemental fertilization if required or desired. Choice of fertilizerwill depend on the type of grass used and on other criteria which arewell known in the art. Examples of fertilizers useful in the presentinvention include but are not limited to fertilizers havingnitrogen:phosphorous:potassium ratios of 1:0:0, 1:1:1, 2:1:2 and 2:1:3.After planting, the sod mat 7 (FIG. 1) is typically ready for harvestwithin 10-14 weeks. An important advantage of the method of the presentinvention is that due to the presence of the root impermeable barrier 5the root system 3 (FIG. 1) of the sod grows in a horizontal directionand does not require horizontal cutting during harvesting as doesconventional sod. The only cutting necessary for harvest is along theedges of the sod to allow the sod to be cut to appropriate size androlled for transport. Because of the minimal disturbance to the rootsystem, shock is minimized and root zones are established more quicklyat the site of use. Sod produced by this method is resistant tocompaction, compatible with the root zone profile of the site to whichit will be transplanted, has appropriate percolation rates and waterretention properties and is well suited for use on sports surfacesincluding stadium and golf courses.

I claim:
 1. A transportable turf manufactured to be planted at atransplant site having a sand soil with a predetermined grain size anddistribution profile comprising: a root-impermeable barrier and asoil-less sand based root zone medium useful in the production of turfgrasses in sod form, the soil-less sand based root zone mediumcomprising: (a) from about 60% by weight to about 100% by weight sandwherein the grains of sand have a size ranging from about 0.05 mm toabout 1 mm and wherein the grains of sand have a grain sizesubstantially matching the grain size of sand at the transplant site;(b) from about 40% by weight to about 0% by weight organic amendment;and (c) an effective amount of fertilizer.
 2. The transportable turfaccording to claim 1 wherein the organic amendment is selected from thegroup consisting of peat mosses, rice hull compost, milorganite,processed sludge, fibrous plant materials, or organic polymers.
 3. Thetransportable turf according to claim 1 wherein the organic amendment isCanadian sphagnum peat moss.
 4. The transportable turf according toclaim 1 wherein the root zone medium contains about 80% by weight sandand about 20% by weight organic amendment.
 5. The transportable turfaccording to claim 4 wherein the organic amendment is Canadian sphagnumpeat moss.
 6. The transportable turf according to claim 1 wherein theroot zone medium contains about 70% by weight sand and about 30% byweight organic amendment.
 7. The transportable turf according to claim 6wherein the organic amendment is Canadian sphagnum peat moss.
 8. Thetransportable turf according to claim 1 wherein the grains of sand havea uniform size ranging from about 0.18 mm to about 0.84 mm.
 9. Thetransportable turf according to claim 1 wherein the fertilizer has a1:1:1 ratio of nitrogen:phosphorous:potassium.
 10. The transportableturf according to claim 1 wherein the fertilizer has a 0:1:1 ratio ofnitrogen:phosphorous:potassium.
 11. A method of cultivating, developingand growing turf grass in sod form, the method comprising the steps ofa) determining the grain size and distribution of sand at a transplantsite; b) blending a soil-less sand based root zone material to form asoil-less blend that has a grain size and distribution of sand thatsubstantially matches the grain size and distribution of the grain sizeand distribution at the transplant site; c) laying down a rootimpermeable barrier; d) depositing a layer of said soil-less blendsufficient for production of turf grass on top of said rootimpermeable-barrier; e) introducing seeds, stolons, sprigs or plugs of aturf grass into the soil-less sand based root zone medium; f)propogating said seeds, stolons, sprigs or plugs into a harvestable matof combined turf grass sod and root zone medium characterized by havinga grain size and distribution of sand that substantially matches thegrain size and distribution of sand at said transplant site; g) whereinsaid root zone medium comprises: (i) from about 60% by weight to about100% by weight sand; (ii) from about 40% by weight to about 0% by weightorganic amendment; and (iii) an-affective amount of fertilizer.
 12. Themethod of claim 11 wherein said organic amendments are selected from thegroup consisting of peats, processed sludge, rice hulls, fibrous plantmaterials, or organic polymers.
 13. The method of claim 11 wherein theorganic amendment is Canadian sphagnum peat moss.
 14. The method ofclaim 11 wherein the root zone medium contains about 80% by weight sandand about 20% by weight organic amendment.
 15. The method of claim 14wherein the organic amendment is Canadian sphagnum peat moss.
 16. Thesoil-less sand based root zone medium of claim 11 wherein the root zonemedium contains about 70% by weight sand and about 30% by weight organicamendment.
 17. The soil-less sand based root zone medium of claim 16wherein the organic amendment is Canadian sphagnum peat moss.
 18. Thesoil-less sand based root zone medium of claim 11 wherein the sandgrains have a uniform size ranging from about 0.05 mm to about 1 mm. 19.The method of claim 11 further comprising blending grass seed with thesoil-less sand based root zone medium prior to deposition on the rootimpermeable layer.
 20. The method of claim 11 wherein the rootimpermeable layer is a synthetic material.
 21. The root impermeablelayer of claim 20 wherein the synthetic material is polyethylene.
 22. Asod mat produced by the method of claim 11 comprising a mat of turfgrass and a layer of soil-less sand based root zone medium.
 23. A sodmat according to claim 22 wherein the grass is a Bermuda grass.
 24. Asod mat according to claim 11 wherein the grass is a Zoysia grass.
 25. Asod mat according to claim 11 wherein the grass is a bent grass.
 26. Asod mat according to claim 11 wherein the grass is selected from thegroup consisting of Fescues, Rye or. Buffalo grass.
 27. A method ofcultivating, developing and growing turf grass in sod form, the methodcomprising the steps of a) determining the grain size and distributionof sand at a transplant site; b) blending a soil-less sand based rootzone material to form a soil-less blend that has a grain size anddistribution of sand that substantially matches the grain size anddistribution of the grain size and distribution at the transplant site;c) laying down a root impermeable barrier; d) depositing a layer of saidsoil-less blend sufficient for production of turf grass on top of saidroot impermeable barrier; e) introducing seeds, stolons, sprigs or plugsof a turf grass into the soil-less sand based root zone medium; f)propagating said seeds, stolons, sprigs or plugs into a harvestable matof combined turf grass sod and root zone medium characterized by havinga grain size and distribution of sand that substantially matches thegrain size and distribution of sand at said transplant site; g) whereinsaid root zone medium comprises: (i) from about 60% by weight to about100% by weight sand; (ii) from about 40% by weight to about 0% by weightorganic amendment; and (iii) an affective amount of fertilizer.